The present invention relates to a system for indicating the level of fuel contained in the tank of a motor vehicle provided with an internal combustion engine.
Fuel tanks of modern motor vehicles often have extremely irregular shape and disposition. This, in one sense, results in the fact that the indication of the level of fuel in the tank, typically provided by a sensor of one of the various known types, is not easily convertible into a reliable indication of the quantity of fuel available. Indication of the level or quantity of fuel is moreover strongly influenced by variations in the attitude of the vehicle.
Unreliability in the information relating to the quantity of fuel available has a particularly negative impact on the motor vehicle user upon starting out (beginning of a trip or journey) and, during journeys, on inclined roads.
Systems for indicating fuel level currently in use include mechanical, electromechanical or electronic xe2x80x9cdampingxe2x80x9d means (in the case of electronic damping this is achieved via hardware and/or software) which makes it possible to attenuate the oscillations of the indication provided to the user upon variation in the level of the fuel in the tank due to swashing and in general, to oscillations in the level due to manoeuvres or dynamic conditions involving rapid variations of the vehicle such as accelerations, braking etc. Such systems thus allow rapid dynamic variations in the level of the fuel which, in fact, do not correspond to effective variations in the quantity of fuel available in the tank, to be xe2x80x9cfilteredxe2x80x9d.
These damping systems do not, however, allow an indication of the level or quantity of fuel to be provided which makes it possible to discriminate between the possible various causes of effective variations in the level of the fuel, such as travelling on an incline, refuelling or re-filling the tank, or the loss of fuel upon rupture or breakage, or theft thereof.
In relation to the fuel level or quantity indicator the satisfaction of the user is related to the fact that during a journey the system should give a sensation of xe2x80x9creliabilityxe2x80x9d in the sense that the information appears to be effectively correlated to the consumption corresponding to the use of the engine""s power. The user can become truly alarmed by sudden variations in the indication of the level or quantity of fuel available if they occur in an essentially non-synchronised manner with corresponding variations in the operating conditions.
When a motor vehicle travels up or down an incline, or is subject to strong longitudinal and/or transverse accelerations the morphology of the fuel tank can be such as to cause a consistent displacement of the volume of fuel contained in it, which can be the source of errors in the indication provided to the user by a display device provided in the instrument panel. Such errors can be unacceptable.
The object of the present invention is to provide a system for indicating the level or quantity of fuel in a motor vehicle tank which makes it possible to obviate the above delineated disadvantages.